New findings of (Eugaleaspiformes, Galeaspida) from the Xiaoxi Formation in South China and their biostratigraphic significance.

New discoveries of the late Silurian fossil fish (Eugaleaspidae, Eugaleaspiformes, Galeaspida), sp. nov. and sp.

Spiny chondrichthyan from the lower Silurian of South China.

Modern representatives of chondrichthyans (cartilaginous fishes) and osteichthyans (bony fishes and tetrapods) have contrasting skeletal anatomies and developmental trajectories that underscore the distant evolutionary split of the two clades. Recent work on upper Silurian and Devonian jawed vertebrates has revealed similar skeletal conditions that blur the conventional distinctions between osteichthyans, chondrichthyans and their jawed gnathostome ancestors. Here we describe the remains (dermal plates, scales and fin spines) of a chondrichthyan, Fanjingshania renovata gen.

The oldest gnathostome teeth.

Mandibular teeth and dentitions are features of jawed vertebrates that were first acquired by the Palaeozoic ancestors of living chondrichthyans and osteichthyans. The fossil record currently points to the latter part of the Silurian period (around 425 million years ago) as a minimum date for the appearance of gnathostome teeth and to the evolution of growth and replacement mechanisms of mandibular dentitions in the subsequent Devonian period. Here we provide, to our knowledge, the earliest direct evidence for jawed vertebrates by describing Qianodus duplicis, a new genus and species of an early Silurian gnathostome based on isolated tooth whorls from Guizhou province, China.

A new Silurian fish close to the common ancestor of modern gnathostomes.

The Silurian Period occupies a pivotal stage in the unfolding of key evolutionary events, including the rise of jawed vertebrates. However, the understanding of this early diversification is often hampered by the patchy nature of the Silurian fossil record, with the articulated specimens of jawed vertebrates only known in isolated localities, most notably Qujing, Yunnan, China. Here, we report a new Silurian maxillate placoderm, Bianchengichthys micros, from the Ludlow of Chongqing, with a near-complete dermatoskeleton preserved in articulation.

scale remains (stem Chondrichthyes) from the Lower Devonian of Qujing, Yunnan, China.

Based initially on microfossils, is one of the first known 'acanthodians', which constitute a paraphyletic assemblage of plesiomorphic members of the total group Chondrichthyes. Its wide distribution has potential implications for stratigraphic comparisons worldwide. Six species of have been reported in China, including one species from the Xitun Formation (Lochkovian, Lower Devonian) of Qujing, eastern Yunnan.